With recent high integration of semiconductor elements and high density mounting of electronic parts on circuit substrates, the number of signal wiring units, connection terminals and electrodes on contact objects has increased, and the spacing therebetween has also become closer.
The electronic parts are usually checked with respect to their characteristics and qualities at every stage of their manufacturing process. For example, at a stage at which a number of LSIs are formed on a silicon wafer or at a stage at which they are parted (the substances at these stages are hereinafter referred to as "bare chips"), a probe is required which can make contact with minute inspection objects densely arranged in an about 4 to 15 mm square region, simultaneously at multiple points with high reliability.
Further, when the above-described bare chips are directly integrated into a product, or at a stage at which a substrate densely provided with a number of electronic parts is integrated into a product together with other circuit blocks, a connecting structure which enables them to connect to a number of densely arranged contact objects with high reliability is also required, as is the case with the inspections at the above-described stages.
A connecting structure using a flexible circuit substrate having projecting bump contacts on a surface thereof is known as a structure which can effect temporary contact or lasting connection to the above-described contact objects formed minutely and densely.
FIG. 6 is a partial sectional schematic view showing a conventional flexible circuit substrate and a connected state thereof to a contact object. Referring to FIG. 6, a, is a conventional flexible circuit substrate in which a plurality of bump contacts 2 mounted on one surface of an electrically insulating film 1 are electrically connected to circuit patterns 3 provided on either surface of the film 1 or on an under layer of an electrically insulating protective film 4. The flexible circuit substrate a.sub.1 is laminated with a contact object b such that a plurality of portions 5 to be contacted on the contact object b such as an electric part are contacted with the above-described bump contacts 2, corresponding to each other. Pressure F is applied to the entire surfaces of the laminate in a compressing direction from the respective opposite surfaces of pressurizing means 6a and 6b which are provided such that the laminate is pinched therebetween in a laminating direction. Thus, the portions 5 to be contacted are contacted with the bump contacts 2, corresponding to each other.
However, the height of the bump contacts themselves fluctuates by manufacturing errors, and in addition to this, the uniformities in the thickness of the electrically insulating film 1, the height of the portions 5 to be contacted on the contact object b, the flatness of a pressurizing surface of the pressurizing means 6a, and the parallelism between the pressurizing means 6a and 6b are all accumulated in the laminating direction. It is therefore very difficult to uniformly contact all the bump contacts 2 with the corresponding portions 5 to be contacted. In particular, as shown in a portion enclosed with an alternate long and short dash line X in FIG. 6, a failure to contact the bump contact 2 with the portion 5 to be contacted causes such a connecting structure to lose contact reliability, which raises a serious problem.